Chapters: add functionality to seek to the nearest chapter on click

This is not implemented particularly gracefully. Currently, it must be
bound to a separate button than standard click to seek, and it will
always seek to a chapter, even if the mouse is not particularly close
to a chapter marker.

It might make sense to have a setting that seeks to a chapter if the
mouse is within a certain threshold of the chapter marker, but that's
more difficult to implement and also requires pixels-on-screen
computation for the hitbox, which is messy.

This feature is disabled by default for backward compatibility, since
the default keybindings have MBTN_RIGHT bound to cycle pause.

src/ActivityZone.moon

@@ -15,13 +15,13 @@ class ActivityZone extends Rect
 		@elements\remove element
 
 	-- bottom-up click propagation does not deal with mouse down/up events.
-	clickHandler: =>
+	clickHandler: ( button ) =>
 		unless @containsPoint Mouse.clickX, Mouse.clickY
 			return
 
 		for _, element in ipairs @elements
 			-- if clickHandler returns false, the click stops propagating.
-			if element.clickHandler and not element\clickHandler!
+			if element.clickHandler and element\clickHandler( button ) == false
 				break
 
 	activityCheck: ( displayRequested ) =>
@@ -41,7 +41,7 @@ class ActivityZone extends Rect
 			for id, element in ipairs @elements
 				element\activate nowActive
 
-		if clickPending
-			@clickHandler!
+		if clickPending != false
+			@clickHandler clickPending
 
 		return nowActive

src/Chapters.moon

@@ -39,6 +39,32 @@ class Chapters extends BarBase
 		@createMarkers!
 		@animation = Animation 0, 1, @animationDuration, @\animate
 
+	clickHandler: ( button ) =>
+		if button == 2
+			@seekNearestChapter Mouse.clickX / Window.w
+			return false
+
+	seekNearestChapter: ( frac ) =>
+		chapters = mp.get_property_native 'chapter-list', { }
+		if #chapters == 0
+			return
+
+		duration = mp.get_property_number( 'duration', 0 )
+		time = duration * frac
+
+		-- could make this a bisection ehhhhh
+		mindist = duration
+		minidx = #chapters
+		for idx, chap in ipairs chapters
+			dist = math.abs chap.time - time
+			if dist < mindist
+				mindist = dist
+				minidx = idx
+			elseif dist > mindist
+				break
+
+		mp.set_property_native 'chapter', minidx - 1
+
 	resize: =>
 		for i, marker in ipairs @markers
 			marker\resize!

src/Mouse.moon

@@ -15,27 +15,33 @@ class Mouse
 		@x, @y = scaledPosition @
 		if @dead and (oldX != @x or oldY != @y)
 			@dead = false
-		if not @dead and @clickPending
+		if not @dead and @clickPending != false
+			button = @clickPending
 			@clickPending = false
-			return true
+			return button
 		return false
 
-	@cacheClick: =>
+	@cacheClick: (button) =>
 		if not @dead
 			@clickX, @clickY = scaledPosition @
-			@clickPending = true
+			@clickPending = button
 		else
 			@dead = false
 
-mp.add_key_binding "mouse_btn0", "left-click", ->
-	Mouse\cacheClick!
+mp.add_key_binding 'MBTN_LEFT', 'left-click', ->
+	Mouse\cacheClick 0
+
+
+if settings['enable-chapter-seek']
+	mp.add_key_binding settings['chapter-seek-button'], 'chapter-seek-click', ->
+		Mouse\cacheClick 2
 
 mp.observe_property 'fullscreen', 'bool', ->
 	Mouse\update!
 	Mouse.dead = true
 
-mp.add_forced_key_binding "mouse_leave", "mouse-leave", ->
+mp.add_forced_key_binding 'mouse_leave', 'mouse-leave', ->
 	Mouse.inWindow = false
 
-mp.add_forced_key_binding "mouse_enter", "mouse-enter", ->
+mp.add_forced_key_binding 'mouse_enter', 'mouse-enter', ->
 	Mouse.inWindow = true

src/ProgressBar.moon

@@ -15,8 +15,13 @@ class ProgressBar extends BarBase
 		@line[7] = [[]]
 		@line[8] = @line[8]\format settings['bar-foreground-style']
 
-	clickHandler: =>
-		mp.commandv "seek", Mouse.clickX*100/Window.w, seekString
+	clickHandler: ( button ) =>
+		if button == 0
+			@seek Mouse.clickX * 100 / Window.w
+			return false
+
+	seek: ( percent ) =>
+		mp.commandv 'seek', percent, seekString
 
 	resize: =>
 		super!

src/settings.moon

@@ -345,6 +345,20 @@ number of chapters may slow down the script somewhat, but I have yet to run
 into this being a problem.
 ]]
 
+settings['enable-chapter-seek'] = false
+helpText['enable-chapter-seek'] = [[
+If enabled and the item being played back has chapters, using the
+`chapter-seek-button` while the progress bar is hovered will seek the video to
+the chapter that is closest to the mouse cursor's position.
+]]
+
+settings['chapter-seek-button'] = 'MBTN_RIGHT'
+helpText['chapter-seek-button'] = [[
+The button to register for chapter seeking, if enabled. Since chapter seeking
+is based on the mouse position, this should probably be bound to a mouse button,
+but it doesn't have to be.
+]]
+
 settings['chapter-marker-width'] = 2
 helpText['chapter-marker-width'] = [[
 Controls the width of each chapter marker when the progress bar is inactive.

torque-progressbar.conf

@@ -245,6 +245,16 @@ pause-indicator-background-style=\c&H2D2D2D&
 # into this being a problem.
 enable-chapter-markers=yes
 
+# If enabled and the item being played back has chapters, using the
+# `chapter-seek-button` while the progress bar is hovered will seek the video to
+# the chapter that is closest to the mouse cursor's position.
+enable-chapter-seek=no
+
+# The button to register for chapter seeking, if enabled. Since chapter seeking
+# is based on the mouse position, this should probably be bound to a mouse button,
+# but it doesn't have to be.
+chapter-seek-button=MBTN_RIGHT
+
 # Controls the width of each chapter marker when the progress bar is inactive.
 chapter-marker-width=2